feat: Implement workspace system (Task #77)

Self-contained workspaces for parallel demo development.

Structure:
- workspaces/main,test - Demo-specific resources
- assets/common - Shared resources
- workspace.cfg - Configuration per workspace

CMake integration:
- DEMO_WORKSPACE option (defaults to main)
- cmake/ParseWorkspace.cmake - Config parser
- Workspace-relative asset/timeline/music paths

Migration:
- Main demo: demo.seq to workspaces/main/timeline.seq
- Test demo: test_demo.seq to workspaces/test/timeline.seq
- Common shaders: assets/common/shaders
- Workspace shaders: workspaces/*/shaders

Build:
cmake -B build -DDEMO_WORKSPACE=main
cmake -B build_test -DDEMO_WORKSPACE=test

All tests passing (36/36).

handoff(Claude): Task #77 workspace system complete. Both main and test workspaces build and pass all tests.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/workspaces/test/shaders/chroma_aberration.wgsl b/workspaces/test/shaders/chroma_aberration.wgsl
new file mode 100644
index 0000000..6c942b7
--- /dev/null
+++ b/workspaces/test/shaders/chroma_aberration.wgsl
@@ -0,0 +1,35 @@
+@group(0) @binding(0) var smplr: sampler;
+@group(0) @binding(1) var txt: texture_2d<f32>;
+
+#include "common_uniforms"
+struct ChromaAberrationParams {
+    offset_scale: f32,
+    angle: f32,
+};
+
+@group(0) @binding(2) var<uniform> uniforms: CommonUniforms;
+@group(0) @binding(3) var<uniform> params: ChromaAberrationParams;
+
+@vertex fn vs_main(@builtin(vertex_index) i: u32) -> @builtin(position) vec4<f32> {
+    var pos = array<vec2<f32>, 3>(
+        vec2<f32>(-1, -1),
+        vec2<f32>(3, -1),
+        vec2<f32>(-1, 3)
+    );
+    return vec4<f32>(pos[i], 0.0, 1.0);
+}
+
+@fragment fn fs_main(@builtin(position) p: vec4<f32>) -> @location(0) vec4<f32> {
+    let uv = p.xy / uniforms.resolution;
+
+    // Compute offset magnitude and direction
+    let offset_mag = params.offset_scale * uniforms.audio_intensity;
+    let offset_dir = vec2<f32>(cos(params.angle), sin(params.angle));
+    let offset = offset_mag * offset_dir;
+
+    // Sample RGB channels with chromatic aberration
+    let r = textureSample(txt, smplr, uv + offset).r;
+    let g = textureSample(txt, smplr, uv).g;
+    let b = textureSample(txt, smplr, uv - offset).b;
+    return vec4<f32>(r, g, b, 1.0);
+}